﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    class Class3
    {
        public double yuanxing (double r){
            return r*r*3.14;
        }
        public int changfangxing(int a, int b) {
            return a * b;
        }
    }
}
